Directions in optical angular momentum

Matt M. Coles; David L. Andrews

doi:10.1117/12.2004430

5 March 2013 Directions in optical angular momentum

Matt M. Coles, David L. Andrews

Proceedings Volume 8637, Complex Light and Optical Forces VII; 863707 (2013) https://doi.org/10.1117/12.2004430
Event: SPIE OPTO, 2013, San Francisco, California, United States

Abstract

For a plane electromagnetic wave, where the electric and magnetic fields are precisely disposed in the transverse plane and the Poynting vector is parallel to the propagation vector, it is well known that the classical text-book analysis of angular momentum density gives a vanishing result for any longitudinal component. In particular, under these assumptions, a circularly-polarized wave (or photon) might be construed to have no angular momentum in the propagation direction. Of course this is untrue; indeed it is the basis of Beth’s famous measurement of spin angular momentum for circularly polarized light that a torque is exerted about the beam axis. This presentation reviews some of the calculational aspects, and the associated physics, involved in a resolution of the issue. In particular it is shown unnecessary to artificially impose on the beam a transverse intensity profile, vanishing at infinity, to resolve the matter. For optical beams of arbitrary structure, promotion of the electromagnetic fields, and associated potentials, to operator form gives non-zero values to each of the commonly deployed electromagnetic measures of physical significance; with a quantum optical formulation, results are cast in terms of Hermitian operators and duly relate to physical observables. Thus, not only energy and angular momentum, but also measures of chirality such as the ‘Lipkin zilch’, acquire a consistent physical interpretation

Citation Download Citation

Matt M. Coles and David L. Andrews "Directions in optical angular momentum ", Proc. SPIE 8637, Complex Light and Optical Forces VII, 863707 (5 March 2013); https://doi.org/10.1117/12.2004430

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available